In their basic configuration, camshaft adjusters generally include a stator which is drivable by a crankshaft of an internal combustion engine and a rotor which is rotatably fixedly connected to the camshaft of the internal combustion engine. An annular space is provided between the stator and the rotor, which is divided into a plurality of working chambers by projections which are rotatably fixedly connected to the stator and project radially to the inside, the working chambers each being divided into two pressure chambers by a vane which projects radially outward from the rotor. Depending on the application of a pressure medium to the pressure chambers, the rotor is adjusted with respect to the stator, and the camshaft is thus also adjusted with respect to the crankshaft, in the “advance” or “retard” direction. The stator and the inwardly projecting projections may be formed, for example, as a single piece from a cup-shaped sintered part, which, however, has the disadvantage that the base surface of the stator acting as the sliding surface must undergo a complex remilling process. A minimum radius in the transitions from the base surface to the projections is unavoidable. As a result of this radius, a slight inner leakage is unavoidable. Furthermore, a slight clearance on the radial bearing between the radial front sides of the projections and the hub of the rotor is unavoidable, due to manufacturing, since the rotor counter-contour may be manufactured only with large tolerances and tool and manufacturing complexity.
A camshaft adjuster is already known from DE 100 24 760 A1, in which the rotor is designed in the manner of a wheel rim having an outer ring and an inner ring, which are connected to each other via webs. The webs divide the annular space between the outer ring and the inner ring into working chambers and assume the function of the vanes known from the prior art. The projections of the stator project laterally into the working chambers and divide each working chamber into two pressure chambers in the known way. The working chambers are delimited both radially inwardly and radially outwardly by walls of the rotor, in the circumferential direction by the webs and laterally by the wall of the stator and the wall of the cover closing the stator.
Due to the proposed shape of the rotor, the sealing surface which was previously provided on the radial outside of the vanes is eliminated, since the vanes no longer rest with their front sides directly against the inner wall of the stator cup and seal the pressure chambers. The previously provided radial bearing of the rotor, formed by the radially inwardly projecting projections of the stator, is furthermore eliminated and replaced by the circular ring-shaped bearing surface of the outer ring of the rotor, which rests against the inner wall of the stator.